Co-crystallization of ionic and neutral supramolecular motifs derived from identical components

The concept of co-crystallization usually applies to the coexistence of two or more different types of molecule in the same crystal, but at a higher level of complexity it is possible to define a parallel concept where a crystal is composed of two or more recognizably different supramolecular assemblies. We describe the structure of an adduct formed between Dianin's compound and ethylene diamine. This structure consists of two recognizably different supramolecular assemblies of these components. Furthermore, these two forms have each previously been observed to exist in isolation. Therefore, it is reasonable to make the comparison with conventional co-crystals where two or more compounds that can exist separately form a crystalline adduct (often termed a "molecular complex").